JPS5918009A - Heater for vehicle equipped with water-cooled engine - Google Patents

Abstract

PURPOSE:To realize normal purification of exhaust gas by putting a selector value on the bypass passage side so as to prevent exhaust gas from being cooled through heat exchange with cooling water in case the temperature of a catalytic converter is lower than the predetermined temperature. CONSTITUTION:The function of a control circuit 24 is such that, during cooling operation a selector valve 12 is put on the heat exchanger 10 side according to signals from a blower switch 7 and water temperature sensor 27 so as to open an opening/closing valve 13, and cooling water is heated by means of an engine E through driving the first water pump and further heated in an exhaust gas passage 9, then room heating is expedited by means of a heater core 5 and warming up operation is expedited. As the warming up operation progresses, the selector valve 12 is put on te bypass 11 side to prevent overheat of the engine E. Further, when catalytic converter CA is detected to have the temperature lower than the temperature capable of purification by means of a temperature sensor 28, cooling of exhaust gas is stopped by putting said valve on the bypass passage side, while overheat is prevented by putting said valve on the heat exchanger 10 side in case the temperature of said converter CA grows abnormally high. Thus, purification of the exhaust gas can be performed normally and overheat of the engine can be prevented.

Description

[Detailed description of the invention] The present invention relates to a heating device for a vehicle equipped with a water-cooled engine.

BACKGROUND ART In vehicles, especially automobiles, heating the interior of the vehicle is essential to improve comfort during winter operation. Currently, if the vehicle is equipped with a water-cooled engine, a hot water type heating system that utilizes the heat of the engine cooling water is used as the heating system.

However, in conventional hot water heating systems, the temperature of the cooling water does not rise sufficiently, especially when the engine is cold, and therefore the heating does not work satisfactorily.

So, Akira Miki! ;j? -7! ;、! ;Otsu 0g is a car heating system that uses the heat of exhaust gas to further heat the cooling water that has been heated to some extent by the engine (cylinder), and uses this further heated cooling water for heating. Proposed.

The heating device described in this published utility model publication further heats the cooling water heated by the engine (cylinder) with exhaust gas, and uses this further heated cooling water for heating, so there is sufficient heat. However, if the cooling water is further heated with air gas in this way, the temperature of the exhaust gas will drop too much, especially if a catalytic converter is used to purify the exhaust gas. There was a risk that abnormal conditions such as failure to obtain a proper purifying effect may occur.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of conventional heating systems, it is an object of the present invention to provide a heating system for a vehicle equipped with a water-cooled engine that can completely prevent the occurrence of abnormal conditions as described above.

The heating device for a vehicle equipped with a water-cooled engine according to the present invention takes out cooling water from a cooling water mantle of the engine body, and includes a heat exchanger installed in an exhaust passage and heated in the vehicle interior by heat exchange with exhaust gas. a heater cooling water circulation path that returns all of the cooling water to the cooling water cannula through the heating heater core;
a bypass passage provided in the exhaust passage and piping the heat exchanger; an abnormal state detection device that detects an abnormal state and generates a signal indicating the abnormal state; and a bypass passage that connects the exhaust passage and the piping. and a switching valve provided at a branch point of the exhaust passage, which normally closes the bypass passage and operates to close the exhaust passage when receiving the signal from the abnormal state detection device. It is something. The abnormal conditions detected by the above abnormal condition detection device are as follows:
For example, the catalyst temperature is low, cooling water is not being supplied to the heat exchanger, the cooling water temperature is abnormally high, or the exhaust gas temperature is low and the cooling water is being cooled down. Can be mentioned. Note that a possible reason for the particularly low exhaust gas temperature 1w is fuel cut during deceleration.

According to the heating device of the present invention, for example, if the temperature of the catalytic converter is biased, it will be detected that the temperature of the catalytic converter has become lower than a predetermined temperature, and the switching valve will be turned on to control the exhaust gas. I made sure to flow it through all the bypass passages and not to the exhaust passage side where the heat exchanger was installed.
The exhaust gas is not cooled by heat exchange with the cooling water, but is supplied to the catalytic converter while being kept at a high temperature, so that the exhaust gas is purified in the catalytic converter under normal conditions. Furthermore, if all of the above-mentioned controls of the present invention are performed by detecting the abnormal commercial temperature state of the cooling water, engine overheating can be prevented, and if all of the above-mentioned controls are performed by detecting the abnormally low temperature sound of the exhaust gas, It is possible to prevent a situation in which the cooling water is cooled in the opposite direction.

A heating system for a vehicle equipped with a water-cooled engine according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a heating system for a vehicle equipped with a water-cooled ennon according to a first embodiment of the present invention.

In FIG. 1, reference numeral E indicates a water-cooled ennon mounted on an automobile (not shown), and a cooling water canopy 1 is provided outside the combustion chamber of this ennon E. This cooling water cannula 1 is divided into upper and lower parts by a partition wall P, and constitutes a cylinder head part water cannula 1a and a cylinder block part water yi b'l.

A cooling water inlet 2 and an outlet 3 are formed in the cylinder head water jacket 1a. The water inlet 2 and the outlet 3 are communicated with each other by a heating cooling water circulation path 4, and a heater core 5, which is a heat exchanger for heating the vehicle interior, is interposed in this circulation path 4. . This heater core 5 heats the air sent by the blower 6 by heat exchange with the heated cooling water passing through the heater core 5. This heated air is introduced into the vehicle interior for heating purposes. The blower 6 is turned off, for example.
It is operated by a manual blower switch 7 having ranges of , LOW, and Hi.

In the figure, reference numeral 8 indicates an exhaust manifold, and an exhaust passage 9 is connected to the exhaust manifold 8. A heat exchanger 10 is provided in the middle of the exhaust passage 9 between the outlet 3 of the circulation route 4 and the heater core 5, and the cooling water sent to the heater core 5 through the entire circulation route 4 is It is heated by the exhaust gas in this heat exchanger 1°. A bypass passage 11 is formed in the exhaust passage 9 to bypass a portion where the heat exchanger 10 is provided. This bypass passage 11 allows exhaust gas to flow when the temperature of the cooling water flowing into the circulation column 4 from the outlet 3 is sufficiently high and there is no need to worry about heating it with the cooling water gold heat exchanger 10. It is for. For this reason, a switching valve 12 is provided at the branching part of the bypass passage 11 from the exhaust passage 9 to adjust and flow the exhaust gas between the exhaust passage 9 where the heat exchanger 10 is provided and the bypass passage 11. It looks like this.

An on-off valve 13 is provided on the upstream side of the heater core 5 in the circulation passage 4, and this on-off valve 13 is closed when the heating device is not needed to prevent cooling water from being sent to the heater core 5.

The circulation path 4 is provided with a passage 14 that bypasses the heater core 5 and the heat converter 10.

This pie? The bypass passage 14 is provided with a radiator 15 that cools the cooling water flowing through the bypass passage 14 . This bypass passage 14 supplies cooling water to a circulation path 4 on the heat converter 10 and heater core 5 side when heating is not performed.
This is to prevent it from flowing into the environment. For this reason, a switching valve 16 is provided at the branch part of the circulation 3JM path 4 and the binos passage 14, and the cooling water is transferred between the circulation path 4 where the heat Y exchanger 10 etc. is provided and the path A's passage 14. The flow can be adjusted between.

On the other hand, the cylinder block water jacket 1b is also formed with an inlet 17 and an outlet 17 for cooling water.

A radiator 21 is provided in the circulation path 20 between the inlet 17 and the outlet 18 for the Rano x -p.

The heating circulation path 4 and the lanoator circulation path 20 are independent from each other. Therefore,
A first water pump 22 is provided in the circulation path 4, and a third water pump 23 is provided in the circulation path 2o, respectively. The first water pump 22 is driven and controlled by a control circuit 24 consisting of a microcomputer, while the first water pump 23 is driven by the engine E.

A bypass passage 25 that bypasses the radiator 21 is provided in the circulation path 20 . This pie A? path 2
5 is for helping warm up the engine by circulating the cooling water without passing it through the radiator 21 completely when the engine is cold. For this reason, a thermostatic valve 26 is provided at the branching portion of the circulation passage 20 and the bypass passage 25 to allow cooling water to flow into the bypass passage 25 until the engine is sufficiently warmed up.

The exhaust passage 9 is provided with a catalytic converter CA for purifying the exhaust gas flowing through the passage 9. This catalytic converter CA purifies exhaust gas through the action of a catalyst, and in order to perform this purification action sufficiently efficiently, the temperature of the catalyst or the temperature of the exhaust gas must be above a predetermined temperature. is important.

The cylinder head water cannula 1a is provided with a water temperature sensor 27 that detects the temperature of cooling water in this portion, and the catalytic converter CA is provided with a temperature sensor 28 that detects the internal temperature thereof. Output ends of the water temperature sensor 27 and temperature sensor 28 are respectively connected to the input end of the control circuit 240. A blower switch 7 is connected to the other input terminal of this control circuit 24, and the control circuit 2
4 is a signal S□ indicating ON/OFF of the heater from the blower switch 7, a signal S2 indicating the cooling water temperature from the water temperature sensor 27, and a catalytic converter C from the temperature sensor 28.
In response to the signal S3 indicating the temperature of A, the switching valve 12
．． 16 and the opening/closing valve 13.

Next, the operation of the heating device having the structure described above will be explained.

First, the operation of the heating system when the engine E is in a cold operating state will be explained. The blower switch 7 of the heating device is moved from the OFF to the ON range of LOW or Hl, and a signal S□ indicating this and the water temperature sensor 27
When the empty signal S2 is input to the partition 1 device 24, this control 1 circuit 24 switches the switching valve 12 to the pipe i9 path 1.
1 to the closed position, and open the on-off valve 13. Since the temperature of the cooling water is low when the blower switch 7 is turned on, the switching valve 16 is opened so that the cooling water flows to the circulation path 4 side. On the other hand, since the temperature and pressure of the cooling water is low, the thermostatic valve 26 is opened so that the cooling water flows into the bypass passage 25.

Further, the control circuit 24 drives the second water pump 22 using the signal S from the blower switch 7 to circulate the cooling water in the circulation path 4 . The cooling water circulated in the circulation path 4 is heated by the cylinder head of the engine E in the cylinder head water cannula 1a. The cooling water heated by the cylinder head flows into the circulation path 4 from the outlet 3 and is passed through the heat exchanger 10 into the exhaust path 9.
It is further heated by the exhaust gas flowing through it. This further heated cooling water is sent to the heater core 5.

The heater core 5 heats the air sent from the blower 6 and sends it into the vehicle interior to heat the entire vehicle interior. The cooling water that has passed through the heater core 5 is returned to IW by the water pump 22.
, is returned from the inlet 2 to the cylinder head water cannula 1a. In this way, the cooling water is sufficiently heated by the relatively high temperature cylinder head and the heat exchanger 10, so the Ennon E
It is possible to obtain sufficient heating temperature even when the temperature is low.

When the engine E has warmed up and the temperature of the cooling water in the cylinder head water mantle 1a has increased to more than YlrA degrees, the total water temperature sensor 27 detects that the control circuit 24 and the changeover switch 12 11 is opened, and the heat exchanger 10 side of the exhaust passage 9 is set to be closed. Thus, heating of the cooling water by the exhaust gas in the heat exchanger 10 is stopped, and overheating of the cooling water and the engine is completely prevented. At this time, since the cooling water temperature is high as described above, the switching valve 16 is also set by the control circuit 24 so as to gradually pass the cooling water to the bypass passage 14 side. The cooling water flowing toward the bypass passage 14 is cooled in the radiator 15 and joins with the cooling water passing through the circulation path 4 to lower the temperature of the entire cooling water. Thus, from this point as well, overheating of the cooling water and the cylinder head of the engine E is prevented.

On the other hand, the Yu-th water pump 023 is driven by the engine E to circulate the cooling water to the circulation path 20.
As mentioned above, when the engine/non-E is cold, the thermostat valve 26 is set to flow the cooling water to the pipe/gas passage 25, so the cooling water flows through the radiator 21.
, and thus does not dissipate all heat, thus promoting the warming up of Ennon E. Engine E is warming up 1
When the temperature of the cooling water circulating in the j-hole channel 20 reaches a predetermined temperature or higher, the thermostatic valve 26 gradually opens to allow the cooling water to flow to the radiator 21, and thus the cooling water is cooled in the radiator 21, and the cooling water is cooled. Prevents overheating of the water and Ennon E cylinder block.

The control circuit 24 also receives a signal S3 from the temperature sensor 28.
If the temperature of the catalytic converter CA is higher than that of the converter C
When it is detected that the temperature has become lower than the lowest temperature at which the exhaust gas can be efficiently purified in A, the switching valve 12 is set to flow the exhaust gas to the bypass passage 11 side with priority over other control systems.

Thus, the exhaust gas is supplied to the catalytic converter CA at a high temperature without losing heat through heat exchange with the cooling water, thus maintaining the purification performance of the catalytic converter CA.
do.

In the above heating device, the /th water pump 022
Basically, when the heating system is in operation, it is rotated at a certain related rotational speed to warm up the system quickly, and when the heating system is not in use, the temperature of the cooling water detected by the water temperature sensor 27, the engine load, the rotational speed, etc. The rotation may be set accordingly, or the water pump 22 may be stopped during cranking.

For example, when the water pump 22 is controlled according to the temperature of the cooling water when the heating device is not in use, the temperature of the cooling water detected by the water temperature sensor 27 is set to a first predetermined temperature 1□ as shown in FIG. The water pump 22 is operated at a constant low speed until the circulating cooling water reaches the engine E.
In order to ensure that the cooling water is sufficiently heated, or to prevent Ennon E from being locally overheated, and then the cooling water temperature reaches a sufficient temperature T2, the water pump is turned on as the cooling water temperature rises. 22 to prevent the engine from overheating, and then operate at a constant rotation speed. The case where the operation of the water pump 22 is controlled according to the cooling water temperature 1!31 has been explained above, but since local overheating of the engine E may occur even when the load increases, Similarly, it is desirable to fully control the rotational speed of the water pump 22 in response to an increase in load. Further, when starting the engine, that is, during cranking, it is desirable to temporarily stop the operation of the water pump 22 as described above in order to prevent deterioration of startability due to the low voltage caused by the operation of the water pump 22. Yes.

In order to perform the above control, in addition to the water temperature sensor 27,
It is necessary to provide an engine load sensor, an engine speed sensor, and a cranking sensor, and to input the output signals of these sensors to the control circuit.

In the above embodiments, the operation of the water pump 22 has been described as being controlled by the control circuit 24 using a microcomputer, but this control may also be performed by an electric circuit as shown in FIG.

The electric circuit 30 shown in FIG. 3 is a drive control circuit for the water pump 22, and includes a differential amplifier 31 and a drive transistor 32 whose base is connected to the output terminal of the differential amplifier 31. A water temperature sensor 27 is connected to one input end of the differential amplifier 31, and a constant voltage generator 33 that generates a constant voltage Vr is connected to the other input end.

The differential amplifier 31 connects the constant voltage Vr and the water temperature sensor 2.
1 detects the temperature of the cooling water in the cylinder head water cannula 1a, compares it with the output signal S2, and outputs the entire difference signal Sd. When the cooling water temperature is above T, the transistor 32 controls the operation of the water pump 51 with a current according to the difference signal Sd2 as shown in FIG. As mentioned above, the Bonn 7°22 is operated until the cooling water reaches the predetermined temperature T0.
Since it is desirable to rotate at a constant low speed, the pump 22 is also connected to a power source 34 which generates a constant low voltage. In addition, a contact 7' that interlocks with the above-mentioned blower switch I is interposed in the transistor 320 pace, and when this contact 7' is turned on, that is, when the heating system is activated, the pump 22 is connected to the output of the water temperature sensor 27. It can be rotated at a constant high rotation speed. As described above, the pump 22 is driven as a whole as shown in FIG. 1 when the heating device is not used, but when cranking, that is, when starting the ennon, a large amount of current is supplied to the starter St. 7" when Stark St is turned on, in front of the pump 22 as shown in Figure 3? Relay 35ff for cutting off the operating circuit of sensor 22: It is desirable to provide this relay. Note that the differential amplifier 31 outputs the difference signal S until it reaches the above-mentioned predetermined temperature.
The configuration is such that the pump ti rotates at a constant low speed without outputting the pump d.

Next, the electric circuit 36 for electrically controlling the switching/crusive 12 will be explained with reference to FIG. 12 switching is performed. This actuator 37 is driven by a relay switch 39 that is energized by a temperature switch 38 that closes when the temperature of the catalyst controller 9-CA falls below the above-mentioned predetermined temperature. The temperature switch 38 is connected to the row of blower switches rVCil1M. The electricity 1i, +l path 36 with the above configuration is installed, and the IJJ 1% valve 12 is set so that the blower switch 7 is set to Lo.
When wt or Hl is in the ON state, that is, the heating device is in the ON state, and the temperature of the catalytic converter CA is lower than the above-mentioned 19 [constant temperature], the switch can be made to open the stove/gas passage 11.

In the above embodiment, the second σ) water pump 23 was described as being of the type driven by an engine, but it may be electrically controlled.

In addition, in the above embodiment, the partition wall that divides the cooling water cannula 1 into the cylinder head portion and the cylinder block portion is of a complete partition type, but as shown in FIG. An incomplete partition wall P' may be used to allow some cooling water to flow between the head portion and the cylinder block portion. Furthermore, in the above embodiments, a type in which the heating cooling water circulation path 4 and the radiator cooling water circulation path 20 are completely independent was explained, but in FIG.
It is also possible to use a type in which a part is shared as shown in FIG. In this case, as shown in the figure, a thermostat knob 40 is installed at the outlet 18 of the outlet 18 when the cooling water reaches a predetermined temperature or higher. Although it is safe to install the thermostat/Z) rev 41 at the branching part of the passages 4 and 20, there is a concern about the lanoator 16, which is not shown in Fig. 7, and the structure requires only seven water pumps Wp.゛It becomes something special. Note that the water pump Wp is of a type driven by the engine E.

[Brief explanation of the drawing]

FIG. 7 is a schematic diagram of the heating device according to the first embodiment of the present invention. FIG. 2 is a graph showing an example of the operation of the first water pump. FIG. 3 is a graph showing an example of the operation of the first water pump. A circuit diagram showing an example of an electric circuit. Fig. 7 is a circuit diagram showing an example of an electric circuit that operates a switching valve provided at a branch point of an exhaust passage and its bypass passage. Fig. FIG. 2 is a schematic diagram of a heating device according to a third embodiment of the present invention. E... Ennon, 1... Cooling water mantle, 1a... Cylinder head water mantle, 1b... Cylinder block water mantle, 4
... Cooling water circulation passage for heating, 5 ... Heater core, 9
...Exhaust passage, 10...Heat exchanger, 11...Pi/gas passage, 12...Switching valve, 20...Cold split water circulation for radiator. Ring passage, 22nd/th water pump, 23rd...
No. 1 water pump. Patent applicant: Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] Cooling water is taken out from the cooling water canopy of the engine body, is provided in the exhaust passage, passes through a heat exchanger that exchanges heat with exhaust gas, heats the cooling water, and a heater core for heating the vehicle interior, and then transfers the cooling water to the engine. a heater cooling water circulation path that returns to the cooling water cannula; a bypass path provided in the exhaust passage that bypasses the heat exchanger; and an abnormal state detection device that detects an abnormal state and generates a signal indicating the abnormal state. -', a switching valve provided at a branch point between the exhaust passage and the bypass passage, which normally closes the bypass passage and acts to close the exhaust passage when receiving the signal from the abnormal state detection device; Heating system for cars equipped with water-cooled engines.